摘要
目的研究1株临床分离的黏菌素和碳青霉烯类均耐药的大肠埃希菌的耐药机制。方法用Vitek 2 Compact系统进行细菌鉴定;微量肉汤稀释法检测常见抗菌药物的最低抑菌浓度(MIC);改良Hodge试验检测碳青霉烯酶,亚胺培南和乙二胺四乙酸(IPM-EDTA)协同实验检测金属β-内酰胺酶;用聚合酶链式反应(PCR)扩增联合测序技术检测多种耐药基因;用多位点序列分型技术分析菌株的分子分型;用质粒结合试验研究bla_(NDM-6)和mcr-1基因是否通过质粒传播;S1酶切-脉冲场凝胶电泳(S1-PFGE)和Southern印迹杂交分析携带bla_(NDM-6)和mcr-1质粒的分子特征。结果该株大肠埃希菌除替加环素敏感外,对β内酰胺类、氨基糖苷类、喹诺酮类药物耐药且同时对黏菌素类抗生素耐药。改良Hodge试验和IPM-EDTA协同试验结果阳性;PCR基因扩增及测序分析显示该菌株同时携带mcr-1,bla_(NDM-6),bla_(CTX-M-55),bla_(TEM-1),rmtB和aac(6')-Ib-cr;多位点序列分型(MLST)结果为ST156型;S1-PFGE和Southern blot结果显示bla_(NDM-6)基因位于大小约80 bp的质粒上,mcr-1基因位于大小约为33 bp的质粒上。结论同时携带mcr-1和bla_(NDM-6)的泛耐药大肠埃希菌已在临床出现,应引起高度重视。
Objective To study the drug resistant mechanism of an colistin and carbapenem co-resistant Escherichia coli isolated from clinical urine specimen. Methods Bacteria identification was performed by Vitek 2 Compact system; minimum inhibitory concentration（ MIC） of common used antibiotics were determined by broth micro-dilution method. Modified Hodge test and imipenem-edetatl disodium（ IPM-EDTA） synergy test were used to screen the production of carbapenemases and metallo-β-lactamase. PCR amplification and sequencing were used to detect the resistant genes. Molecular genotype was analyzed using MLST. Conjugative assays were performed to study the transferability of mcr-1 and bla（NDM-6） genes. Plasmid analysis was performed through S1-PFGE and Southern blot hybridization. Results This isolate was identified as Escherichia coli. In vitro antimicrobial susceptibility tests showed that the strain was resistant to all antibiotics except tigecycline.The Modified Hodge test and IPM-EDTA synergy test indicated this strainproducing metallo-β-lactamase. Resistant genes of bla（NDM-6）,bla（CTX-M-55）,bla（TEM-1）,rmt B,aac（ 6＇）-Ib-cr and mcr-1 were detected by PCR amplification and sequencing. Molecular genotype of the strain was ST156. Results of S1-PFGE and Southern blot hybridization showed that bla（NDM-6） was located in the plasmid with size of about 80 bp and mcr-1 was located in the plasmid with size of about 33 bp. Conclusion Extensive drug resistant Escherichia coli carrying MCR-1 and NDM-6 has appeared in clinical isolates and should be highly concerned.
作者
黄旭
孙鹏飞
夏文颖
唐晨杰
倪芳
刘根焰
HUANG Xu, SUN Peng -fei, XIA Wen - ying, TANG Chen - jie, NI Fang, LIU Gen- yan(Department of Laboratory Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanfing 210029, Chin)
出处
《中国临床药理学杂志》
CAS
CSCD
北大核心
2018年第14期1696-1699,共4页
The Chinese Journal of Clinical Pharmacology
基金
江苏省"强卫工程"实验诊断学重点实验室基金资助项目(ZDXKB2016005)
江苏省研究生培养创新工程基金资助项目(SJLX15_0436)
